Problem: Solve the system of equations. $\begin{aligned} & -4x+11y = 15 \\\\ & x=2y \end{aligned}$ $ x=$
Answer: We are given that ${x}={2y}$. Let's substitute this expression into the first equation and solve for $y$ as follows: $ \begin{aligned} -4{x}+11y &= 15\\\\ -4\cdot{2y}+11y&=15\\\\ -8y+11y&=15\\\\ 3y&=15\\\\ y&=5 \end{aligned}$ Since we now know that ${y}={5}$, we can substitute this value in the second equation to solve for $x$ as follows: $\begin{aligned} x &= 2\cdot{y} \\\\ x&=2\cdot{5}\\\\ x&=10 \end{aligned}$ This is the solution of the system: $\begin{aligned} &x = 10 \\\\ &y=5 \end{aligned}$